Fuel tank assembly

ABSTRACT

A vehicular fuel tank assembly comprising a steel outer container and a pliable inner member such as a liner or diaphragm having a plurality of circular folds in a substantially horizontal wall portion thereof to permit the center of the wall to collapse telescopically and vertically relative to the bottom of the container as fuel is exhausted from the tank assembly. This telescopic collapse provides volumetric variation in the fuel storage area and further provides variable anti-slosh baffling for the unused fuel. A control valve regulates air flow into and out of the exhausted space between the container and the internal member. Fuel gaging is accomplished by monitoring the displacement of the collapsible internal member portion relative to the container. The container is mounted on the vehicle to permit limited damped longitudinal displacement under abnormally high acceleration load conditions.

ama- 50R? ans-6. 686

United States Patent [191 Pringle l l Sept. 4, 1973 i 1 FUEL TANKASSEMBLY [75] inventor: William L. Pringle, Grosse Pointe pmfury f TQuelsscr Shores Mich. ASSlAIdfll lzxammer-Denis E. CorrAttornvr-(leraltl E. Mcblynn. Jll. Harold W. [73] Assignee: William L.Pringle and Associates, MmonJn at L lnc., Detroit, Mich.

[22] Filed: Dec. 10, 1971 [57] ABSTRACT [21] APPL 206,756 A vehicularfuel tank assembly comprising a steel outer container and a pliableinner member such as a liner or Related Apphcatw Data diaphragm having aplurality of circular folds in a sub- 1 Division of 36,022, stantiallyhorizontal wall portion thereof to permit the 31,48,836- center of thewall to collapse telescopically and vertically relative to the bottom ofthe container as fuel is [52] [1.8. Cl 73/290 R exhausted from the kassembly This telescopic COL I51 I Int. Cl. G0 23/00 lapse providesvoumctric variation in the fuel storage [58] Field of Search 73/290 R,313; area and further provides variable ami slosh baffling 338/41* 42for the unused fuel. A control valve regulates air flow into and out ofthe exhausted space between the con- 1 References Cited tainer and theinternal member. Fuel gaging is accom- UNITED STATES PATENTS plished bymonitoring the displacement of the collaps- 2,074,959 3 1937 Guest 73290 R ible internal member portion relative to the n in r- 3,3l4,2924/1967 Schulte 73/290 R The container is mounted on the vehicle topermit lim- 2, 23,l56 2/1960 Youngm 73/313 ited damped longitudinaldisplacement under abnor- 3,l'73,120 3/1965 Marks t. 338/41 mally highacceleration load conditions.

1 Claim. 8 Drawing Figures Patented Sept. 4, 1973 3 Sheets-Sheet lPatented Sept. 4, 1973 v 3,756Q080 3 Sheets-$heet 2 Patented Sept. 4,1973 3,756,080

3 Sheets-Sheet 3 FUEL TANK ASSEMBLY This is a division of applicationSer. No. 36,022, filed May 11, 1970, now US. Pat. No. 3,648,886.

This invention relates to fuel tank assemblies and particularly to animproved fuel tank assembly for vehicles.

The transportation of fuel for consumption by the transporting vehiclegives rise to certain considerations in the areas of safety and airpollution. Safety considerations include (1) excessive sloshing andagitation of fuel in the tank, (2) thermal expansion of fuel in a fulltank with resulting spillage in the vicinity of the vehicle, (3) thesafe and satisfactory monitoring of fuel remaining in the tank, and (4)the escape of fuel from the tank due to damage caused in a collision.Air pollution considerations include (1) the evaporation of fuel from anunsealed tank and fuel distribution system, (2) the overflow of liquidfuel from the tank due to thermal expansion, and (3) the escape ofliquid fuel arising from a rupture or a loss of integrity of the fueltank.

Past efforts to deal with these considerations have generally beencarried out on a piecemeal basis; that is, tank liners and the like havebeen proposed to prevent fuel escape following a loss of integrity ofthe tank itself, baffles have been placed in tanks to reduce sloshingeffects, passive fuel metering systems have been proposed and, finally,sealed fuel tanks have been proposed to prevent overflow andevaporation. None of these piecemeal proposals have involved fuel tankdesigns which deal with two or more of these considerations in acomprehensive and feasible fashion which is suitable for mass productionand which provides economy of fabrication. The present inventionprovides a comprehensive treatment of various fuel tank assemblyconsiderations including those set forth above and results in a fueltank assembly which affords the advantage of a variable volume containerand a variable anti-slosh baffle and which readily admits of scaled fuelsupply operation and nonimmersed fuel metering. In general, this isaccomplished in a tank assembly which includes a substantially rigidouter container and an inner member of relatively pliable materialhaving a portion which divides the interior of the container into fuelstorage and air storage sections. The inner member is designed such thata portion thereof may be displaced in a predetermined and predirectedfashion such as from top to hottgm tg regiprggally vary the volumes ofthe two storage geetigng and to provide, in varying degrees related tothe fuel remaining in the tank, an anti-slosh baffle.

The internal member ay be di p e in the container in various fashions,two preferr fashi n ing disclosed herein. The first fashion inv lvesforming the member as a full liner for the container and the secondinvolves forming the member as a diaphragm which are tends across thecontainer and is retained therein by, for example, a bead which issandwiched into a seam between two container portions.

in the preferred form of the invention, which is illus= trated herein,the internal member includes a portion having concentric folds whichpermit a variable tcle= scoplc collapse of the internal member relativeto the bottom of the container as fuel is exhausted from the containerthereby to accomplish the aforementioned volumetric variation and theanti-slash baffle effect. Moreover, the folds of the internal member arepreferably formed in a spaced, corrugated fashion so as to atford areserve volume within the container for thermal expansion of the fuelthereby to obviate the necessity for overflow conduits and the like.This thermal expansion capability may be complemented with additionalpockets of reserve space between the container and the internal member;for example, such pockets may be disposed peripherally around the tankassembly by suitable formation of the container and the internal linermember.

In accordance with the invention fuel metering is readily accomplishedby substantially conventional metering apparatus, such as the well knownpivotally operated rheostat, but without requiring the immersion ofelectrical apparatus in a volatile fuel reservoir. In general, this isaccomplished by placing the fuel level monitoring apparatus on thecontainer and operatively disposed between the container and thecollapsible portion of the internal member such that the degree ofdisplacement between the container and the displaceable portion of theinternal member determines the signal quantity which is generated by thegaging or fuel level monitoring apparatus. The gaging apparatus is thusexclusively within the air storage section of the subject fuel tankassembly and is not in contact with fuel at any time.

In accordance with another aspect of the invention, increased safetyfrom fuel tank rupture and resulting fuel spillage is accomplished bymeans of a damping type suspension device which permits mounting thecontainer on the vehicle such that a controlled deceleration of the tankobtains in the event of a collision. In general, this involves amounting means including a deformable element secured to the vehicle anda die or die set secured to the tank and engaging the element at or neara predeformed section. Should a collision result in high accelerationforces on the tank, the mounting means permits the tank to be displacedlongitudinally, for example, relative to the vehicle to a limited extentand in an energy damping or absorbing fashion. This controlleddeceleration of the tank relative to the vehicle tends to substantiallydecrease the likelihood of fuel tank rupture in the event of acollision.

Various other features and advantages of the subject invention willbecome more apparent upon reading the following specification whichdescribes several illustrative embodiments of the invention in detail.This specification is to be taken with the accompanying drawings ofwhich:

FIG. 1 is a side view in cross-section of a first embodiment of theinvention in a near-empty condition;

FIG. 2 is a side view in cross-section of the embodiment of FIG. 1 in anear-full condition;

FIG. 3 is an enlarged view of a portion of the embodiment of FIGS. 1 and2 showing circuit details thereof;

FIG. 4 is a plan view of a representative portion of the embodiment ofFIG. 1 taken along the section lines 4==4 thereof;

FIG. 5 is a partial side view in cross section of a second embodiment ofthe invention;

FIG. 6 is a perspective view of a lower tank shell illus= tratlng apreferred mounting arrangement;

FIG. 7 is a side view of a detail of the arrangement of FIG. 6 takenalong a section line 7==7 thereof; and

FIG. 8 is an exploded perspective view of a detail in a mountingarrangement of FIGS. 6 and 7.

Referring now to FIGS. 1 through 4, there is shown an automotive fueltank assembly 10 including a shallow substantially rectangular container12 having an upper steel shell 14 and a lower steel shell 16 joinedtogether such as by welding to form a butt seam 17 around the peripherythereof. Container 12 is provided with a fuel filler pipe 18 whichextends outwardly and upwardly therefrom. Container 12 is furtherprovided with a fuel outlet 20 through which fuel may be drawn byoperation of a conventional fuel pump.

In the embodiment of FIGS. 1 through 4, the tank assembly includes aninternal liner 22 of noncorrosive and relatively pliable material, asuitable material being selected from the groups of materials generallyknown as plastic and elastomers. Nylon is the preferred material.Internal liner 22 is formed with an upper wall 24 and a lower wall 26which normally are disposed in spaced relation with one another andwhich over at least portions thereof generally conform to the interiorconfiguration of the container 12. Liner 22 may be bonded to container12 along the bottom and, possibly, at the corners to prevent movementrelative to the container.

The upper wall 24 of the liner 22 has formed therein a plurality ofconcentric circular folds 28 which permit a generally planar centralportion 74 of the liner 22 to be displaced vertically in a telescopicfashion relative to the fixed portions of the assembly 10. As indicatedfrom a comparison of FIGS. 1 and 2, this vertical telescopicdisplacement takes place in response to varying quantities of unusedfuel within the container 12 and operates to vary the volumetric ratiobetween a fuel storage section 30 and an air storage section 32, bothsections being within the confines of the container 12 and the boundarytherebetween being defined by the displaceable portion of the liner 22.

Liner 22 is formed with an outwardly and upwardly extending spoutportion 34 which, on assembly, is drawn through the filler pipe 18 ofthe container 12 as shown in FIGS. 1 and 2. The spout portion 34 ispreferably of greater length than the filler pipe 18 such that theoutermost portion of the spout 34 may be turned back over the annularlip and fixed in place by means of a clamp member 36 having acylindrical portion 38 which extends partially into the filler pipe 18as shown. The location of the liner member 22 within the filler pipe 18of the container 12 is preferably accomplished prior to joining theupper shell 14 to the lower shell 16 and welding the seam l7. Liner 22is preferably made in two or more pieces which are joined together priorto insertion in the container 12.

At the opposite end of the assembly 10 the fuel outlet receives a smalldiameter fuel line 40 which extends into the fuel storage section 30 ofthe container 12 and terminates in a small mesh filter 42 which liesgenerally along the bottom of the tank assembly 10. A recessed area 44is formed in the upper shell 14 of the container 12 to grasp the fuelline 40 and the liner member 22 is preferably drawn through the clampingaperture and extended along the fuel line 40 as shown to effect anadequate seal. Various other assemblies in the area of the fuel line 40and outlet 20 can obviously be used in place of that shown.

When the tank assembly 10 is empty or near empty the planar portion 74of the liner members 22 is permitted by the concentric circular folds 28to drop verticallyand telescopically toward the bottom wall 26 of theliner 22 which bottom wall rests on and conforms to the bottom shell 16of the container 12. Under these conditions the fuel storage section 30is of minimum volume and the air storage section 32 is at maximumvolume. As fuel is admitted to the fuel storage section 30 through thefiller pipe 18 the increasing volume of fuel causes the plane portion 74of the liner member 22 to be displaced vertically upwardly telescopingthe various corrugated convolutions defined by the folds 28 into oneanother until the liner member 22 assumes the configuration shown inFIG. 2. In this configuration the tank assembly 10 is substantially fullof fuel and the volume of the fuel storage section 30 is at a nearmaximum whie the volume of the air storage section 32 is at a nearminimum. Also in this configuration the plane section 74 is at thevertically highest elevation relative to the bottom wall 26 of the linermember 22 which, as previously mentioned, rests on and conforms to thebottom shell 16 ofthe container 12.

It will be observed that because of the rounded or corrugatedconfiguration of the folds 28 a considerable reserve volume of air spaceis provided by the annular spaces between the folds 28 and the uppershell 14 of the container 12. This reserve volume, along with additionalreserve volume to be described, provides a reserve for thermal expansionof the fuel in the fuel storage section 30 such that overflow pipes andfuel collectors are unnecessary. Moreover, as the fuel is withdrawn fromthe container 12 through the fuel line 40, the vertical displacement ofthe plane portion 72 into the center of the fuel tank assembly 10provides an increasing baffle to prevent and inhibit lateral travel orsloshing of the remaining fuel in the container 12. In the configurationshown in FIG. 1 a substantial volume of unused fuel may exist in asomewhat torroidal volumetric configuration within the container 12. Thesloshing of this unused fuel quantity from front to back or side to sidewithin the container 12 is effectively prohibited by the baffle effectof the telescopically displaced portion of the liner member 22.

The anti-slosh feature of the liner member 22 described above isenhanced by controlling the fiow of air from the outside into the airstorage space 32 and, conversely, by controlling the flow of air fromthe air storage portion or section 32 back to the outside. As shown inFIGS. 1 and 2 a small cylindrical recess 46 is provided in the uppershell portion 14 to receive a control valve which performs this air flowcontrol function. The valve is identified by reference character 48 andis shown in detail in FIG. 3.

Referring to FIG. 3 the air control valve 48 comprises an inverted cupportinon 50 having an annular arrangement of holes therein andbeing'fixed to a mounting post 52 which is vertically oriented withinthe cavity 46. A ring 54 is secured to the bottom of the post 52 andoperates as a stop for a second smaller cup member 56 which is disposedconcentrically about the post 52 and within the recess 46. The secondcup member 52 carries about the periphery thereof an annular sealingring 57 which is provided with a beveled surface to contact the interiorsurface of the first cup member 50. A spring 58 operates between the cupmembers 50 and 56 to urge the second cup member 56 toward the stop disc54. Thus, to permit the relatively unimpeded flow of air through theapertures in the first cup member 50, between the cup member 50 and thesealing ring 57 and thence through the aperture 60 in the bottom of thecylindrical recess 46. Accordingly, air at moderate flow rates ispermitted to flow into and out of the air storage section 32 through thenormally open valve 48. However, if the movement of the fuel within thecontainer 12 tends to rapidly decrease the volume of the air storagesection 32 and thus attempt to force the high air flow through the valve48 the increased pressure operates on the cup member 56 to oppose thebias of spring 58 and force the ring 57 into sealing relation with theunder surface of the first cup member 50. This effectively closes theannularly arranged apertures in the cup member 50 and prevents the flowof air from the air storage section 32 to the outside. The overalleffect of the valve 48 is to impede the flow of air, thus, toeffectively stiffen the baffle provided by the telescoping portion ofthe liner member 22 and operate to prevent sloshing of the unusedquantity of fuel within the container 12. Under normal conditions thefree telescopic displacement of the liner member 22 relative to theupper shell 14 of the tank is permitted to allow fuel to be readilyentered into and exhausted from the container 12. Control valve,assemblies having designs other than that shown in FIG. 3 may, ofcourse, be employed.

Referring to FIGS. 1 through 3 the fuel tank assembly is shown toinclude a fuel gaging apparatus 62 of the rheostat type which is mountedon the upper shell 14 of the container 12 and operatively engaged withthe displaceable portion of the liner member 22. The gaging apparatus 62is disposed exclusively within the air storage section of the interiorof the container 12 and operates on the principle of monitoring thedegree of vertical displacement of the plane portion 74 of the linermember 22 within the container 12. Accordingly, the gaging apparatus 62includes a conventional distributed wire resistor portion 64 having awiper (not shown) which is displaced over the distributed wire resistorby means ofa pivotally mounted arm 66. Arm 66 terminates in a roller 68which is disposed against the upper surface of the plane portion 74 ofthe liner member 22 such that the angular orientation of the arm 66relative to the resistor portion 64 of the gaging apparatus 62 isdetermined by the vertical orientation or position of the plane portion74 relative to the bottom of the tank assembly 10. A rigid plate ofmetal or plastic may be placed between roller 68 and liner 22 to preventexcessive wear on the liner. FIG. 1 shows the arm 62 in a maximumangular orientation which would produce a near-empty signal from thegaging apparatus 62.

FIG. 2 shows the arm 66 in the minimum angle position which, of course,would produce a full indication from the gaging apparatus 62. As shownin FIG. 3 the generally plane portion 74 of the liner 22 may bepreformed with a recessed track 72 which is engaged by the roller 68 onthe end of the rheostat arm 66. A suitable received or indicatorapparatus and a suitable voltage source is, of course, to be connectedto the rheostat apparatus 62. This may be accomplished by means ofsuitable electrical connectors including the connector 70 which is shownin some detail in view of FIG. 3.

In summary the gaging apparatus 2 may be employed to monitor thequantity of unused fuel in the tank assembly 10 by monitoring the degreeof vertical displacement of the plane portion of the liner 22 relativeto the bottom wall 26 which rests on and conforms to the bottom wall ofthe container 12. In this manner the gaging apparatus 62 may be like theconventional float controlled type but need not come into contact withthe fuel in the tank assembly 10 at any time. Referring to FIG. 4 thecontainer 12 is shown to be preformed in such a fashion as to provide aplurality of peripherally distributed pockets 76 about the tank assembly10. Moreover, the liner 22 is similarly preformed to have a plurality ofperipherally arranged pockets 78 which register with the pocket 76 inthe container 12 but, as shown in FIG. 4, are more shallow so as toresult in a space between the pocket 78 of the liner 22 and the pocket76 of the container 12. These peripherally disposed pockets providefurther thermal expansion volume to operate in conjunction with thethermal expansion volume provided by the grounded or corrugated folds 28of the liner 22 when disposed in the position of FIG. 2. In addition,the space between the pockets 76 and 78 also operates to provide adegree of resilience in the liner 22, this resilience being effective toprovide a degree of lateral energy absorption due to lateral travel ofthe fuel within the container 12 during motion of the vehicle upon whichthe assembly 10 is mounted.

Referring to FIG. 5, a second embodiment of the invention is shown. Inthe assembly of FIG. 5 the use of primed reference numerals indicatesthe similarity between the assembly of FIG. 5 and the assembly of FIGS.1 through 4.

In FIG. 5 the fuel tank assembly 10 is shown to include a steel outercontainer 12' made up of an upper shell 14' and a lower shell 16'. Thelower shell 16 has mounted thereon a filler pipe assembly 18 throughwhich fuel may be placed in the tank assembly 10'. The assembly 10'further includes a diaphragm member 22' of relatively pliable materialsuch as plastic disposed in a generally horizontal configuration withinthe container l2 and secured in place by means of a peripheral bead 82which is sandwiched between the peripheral portions of the upper shell14 and the lower shell 16' which forms a butt seam l7. Liner 22 isformed with a plurality of concentric circular folds 28' which permit alower plane portion 74 of the diaphragm member 22 to be vertically andtelescopically dis placed relative to the lower shell portion 16 of thecontainer 12. This displacement, of course, operates to vary thevolumetric ratio between the fuel storage section 30 and an air storagesection 32 within the container 12', these two sections being separatedby the diaphragm member 22. The assembly 10' of FIG. 5 is furtherunderstood to include the air flow control valve 48 of FIG. 3 and asuitable fuel outlet means preferably of the type shown in FIGS. 1 and2.

The assembly 10 of FIG. 5 operates substantially like that of assembly10 shown in FIGS. 1 through 4. Accordingly, as fuel is introduced intothe fuel storage section 30' by means of the tiller pipe 18 the planeportion 74 of the diaphragm member 22 is caused to be displaced upwardlythereby to telescope the concentric circular folds 28 in the diaphragmmember 22. This vertical displacement operates to increase the volume ofthe fuel storage section 32 and to correspondingly decrease the volumein the air storage section 32. The degree of extension of the verticallydisplaceable portion of the diaphragm member 22 operates to cause avariable baffling effect as well as to regulate the volumetric ratio aspreviously described. A degree of expansion in the volume of the fueldue to thermal variations is again permitted by the rounded annularsleeve spaces which are defined between the folds 28 and the innersurface of the upper shell portion 14' as was the case in the assembly10 of FIG. 2.

It is to be understood that asuitable gaging apparatus, such as 62 shownin FIGS. 1 through 3, may also be used in conjunction with the assemblyof FIG. 5. The assembly of FIG. 5 does not, of course, provide all ofthe advantages of a full tank assembly liner but does operate to providethe compartmentizing of the container 12', the baffling effect andfurther admits the nonimmersion fuel metering and thermal expansion ofthe contained fuel.

Mounting of the assembly on the vehicle is accomplished by means ofmounting apparatus shown in FIGS. 6, 7 and 8. Referring to thoseFIGURES, FIG. 6 shows the bottom shell 16 of the assembly 10 to haveformed therein a pair of parallel longitudinal channels 84 and 86, saidchannels appearing as recesses in the exterior surface of the shell 16.In addition, channel 84 has formed therein at longitudinally spacedpositions the further recessed pockets 88 and 90. In a similar fashionfurther recessed pockets 92 and 94 are formed at longitudinally spacedpositions in the channel 86. The channels 84 and 86 and the furtherrecessed pockets 88, 90, 92 and 94 operate in conjunction with elongatedmembers 96 and 98 of deformable material, such as steel, to suspend thetank assembly 10 relative to a vehicle such that the imposition ofextremely high acceleration loads on the tank assembly 10 due to acollision of the vehicle carrying the tank assembly 10 with anothervehicle or with a stationary object will permit the tank assembly 10 tobe displaced longitudinally relative to the vehicle over a shortdisplacement length during which an energy absorption process isaccomplished.

Referring to FIG. 7, the details of the mounting structure in thevicinity of the recess 92 in channel 86 are shown in greater detail. Theapparatus in the vicinity of recess 92 is representative of theapparatus to be found in the vicinityof each of the other recesses 88,90 and 94 and, thus, the explanation of one such apparatus will sufficefor all. Disposed within the recess 92 of channel 86 is a first diemember 100 having fingers 102 and 104 which seat the die member firmlywithin the recess 92 and prevent longitudinal or lateral displacementthereof. Die member 102 is further provided with a rounded tongueportion 106 which extends vertically downwardly relative to the recess82 and into the area of'the channel 86. Tongue portion 106 extends intodirect and mating engagement With a deformed section 108 of theelongated strap member 98. A second die member 110 is disposed beneaththe deformed section 106 of the elongated strap member 98 so as tosandwich the strap member .98 between the second die member 110 and thefirst die member 104. Second die member 110 is suitably secured to thefirst die member in this complementary relationship by means of bolts orother fasteners, not shown. Finally, the elongated strap member 98 issecured at both ends to the frame of an automobile as represented by therod 112 in FIG. 8. The elongated strap member 98, along with theparallel strap meMber 96, is preferably oriented in the longitudinaldirection relative to the vehicle to which it is attached.

In operation, the mounting apparatus of FIG. 8 simply secures the tankassembly 10 to the vehicle for transportation therewith under normalconditions. Since the strap members 96 and 98 are rigidly secured to thevehicle and have more than adequate structural strength to hold up thetank assembly 10, the tank assembly 10 may be simply thought of as beingsecurely and immovably cradled within the strap members 96 and 98.However, should a moving vehicle collide with another vehicle or anotheheavy object, the rapid deceleration of the vehicle imposes a highaccelerative force on the tank assembly 10 causing it to continue to betranslated in the direction of original displacement. This accelerativeforce, operating in the longitudinal direction relative to the vehiclecauses the tank assembly 10, along with the die members and which aresecured thereto, to be displaced forwardly thereby deforming the steelstrap members 96 and 98 between the die members in the vicinity of eachof the recesses 88, 90, 92 and 94. This continuous deformation of thesteel strap members 96 and 98 causes a working of the metal whichresults in the absorption of the kinetic energy of the tank assemblyover a short but adequate displacement such that the abnormally highaccelerative loads which would otherwise be imparted to the fuel tankassembly are greatly reduced. This substantial reduction in accelerativeloads tends to decrease the tendency to rupture the fuel tank assemblyand, thus, greatly decreases the risk of fuel spillage followingcollision.

To summarize the invention as illustrated herein, a fuel tank assemblycomprises a relative rigid external steel container 12 (12') and arelatively pliable internal member 22 (22) which divides the interior ofthe container 12 (12') into a fuel storage section 30 (30) and an airstorage section 32 (32). The internal member 22 (22') is provided with aplurality of concentric circular folds 28 (28) which permit a centralportion of the internal member to be displaced telescopically in thevertical direction thereby to vary the volumetric ratio between the fueland air storage sections and variably baffle the interior of the fuelstorage section and prevent the inordinate sloshing of unused fueltherein. Moreover, the flow of air into and out of the air storagesection 32 (32') is regulated by means of a valve 48 which permits onlyrelatively low flow rates and which responds to excessive flow rates toeffectively close against the operation of a bias spring 58.

The tank assembly 10 (10) of the subject invention permits thermalexpansion under varying temperature conditions without the need foroverflow and fuel absorption facilities and further permits the use ofnonimmersed fuel monitoring apparatus 62 which may be disposed on thecontainder 12 (12') so as to monitor fuel as a function of the verticaldisplacement of the central and vertically displaceable portion of theinternal member 22 (22).

Finally, the tank assembly 10 is preferably mounted on a vehicle bymeans of an energy absorbing mounting apparatus which includes adeformable securement member 96, 98 and one or more die members 106, 110which cooperate with the deformable securement member to permit limitedenergy absorbing displacement of the tank assembly 10 relative to thevehicle under high and abnormal accelerative loads thereby to decreasethe accelerative loads imposed on the tank and minimize the risk of fueltank rupture.

It is to be understood that the invention has been described withreference to preferred embodiments thereof in accordance with the patentlaws and that such modifications are to be regarded only asillustrations and not as limiting the invention.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

l. A fuel tank assembly comprising a fixed outer container, an internalmember having a displaceable portion dividing the container into fueland air storage sections of reciprocally variable volumes, said internalmember comprising a diaphragm portion extending substantiallyhorizontally across the interior of the container and having a pluralityof circular folds to permit the center thereof to be displacedvertically within the container in accordance with the fuel quantity insaid fuel storage section, said circular folds defining at the center ofsaid internal member a substantially flat unfolded area having anelongated and recessed track formed therein and gaging means on thecontainer for monitoring the position of the displaceable portion, saidgaging means comprising a fixed portion mounted on said container withinsaid air storage section and a pivotal lever arm extending from saidfixed portion toward said elongated track, bearing means on the end ofsaid lever and in engagement with said track, said lever being pivotallyconnected to said fixed portion and oriented so that the bearing meansrides along said track as said internal member moves vertically withinsaid container, said lever and said fixed portion being mechanically andelectrically interrelated so as to produce an electrical output signalof a variable character representing the vertical position of saidcenter of said internal member within said container.

* i i l

1. A fuel tank assembly comprising a fixed outer container, an internalmember having a displaceable portion dividing the container into fueland air storage sections of reciprocally variable volumes, said internalmember comprising a diaphragm portion extending substantiallyhorizontally across the interior of the container and having a pluralityof circular folds to permit the center thereof to be displacedvertically within the container in accordance with the fuel quantity insaid fuel storage section, said circular folds defining at the center ofsaid internal member a substantially flat unfolded area having anelongated and recessed track formed therein, and gaging means on thecontainer for monitoring the position of the displaceable portion, saidgaging means comprising a fixed portion mounted on said container withinsaid air storage section and a pivotal lever arm extending from saidfixed portion toward said elongated track, bearing means on the end ofsaid lever and in engagement with said track, said lever being pivotallyconnected to said fixed portion and oriented so that the bearing meansrides along said track as said internal member moves vertically withinsaid container, said lever and said fixed portion being mechanically andelectrically interrelated so as to produce an electrical output signalof a variable character representing the vertical position of saidcenter of said internal member within said container.